Enclosed electric safety switch



March 21, 1944. w u s ENCLOSED ELECTRIC SAFETYSWITCH 4 Sheets-Shet 1 Filed April 21, 1941 RT. &0 U m w w m IM m L H Y WB ATTORNEY March 21, 1944. w. .1. QUAST ENCLOSED ELECTRIC SAFETY SWITCH Filed April 21, 1941 4 Sheets-Sheet 2 INVENTOR WILLIAM J. QUAST 02% ATTORNEY March 21, 1944. 4 w, J UAST 2,344,636

v ENCLOSED ELECTRIC SAFETY SWITCH Filed April 21, 1941 4 Sheets-Sheet 5 INVENTOR WILLIAM J- QUAST BY ar ATTORNEY March 21, 1944.

w. J. QUAST ENCLOSED ELECTRIC SAFETY SWITCH Filed April 21, 1941 4 Sheets-Sheet 4 INVENTOR WILLIAM J QUAST ATTORN EY Patented Mar. 21, 1944 UNITED STATES PATENT- OFFICE ENCLOSED ELECTRIC SAFETY swrrcn William J. Quast, Lake, Wis., assignor to Allen- Bradley Company, Milwaukee, Wis., a corporation of Wisconsin Application April 21, 1941, Serial No. 389,565

11 Claims.

switch locked in the off position before the enclosure may be opened, and with the enclosure opened the switch lock being manually releasable for purposes of inspection and test.

A further object of the invention is to secure in an improved enclosed electric safety switch, an enclosure lock, a switch operating means and switch lock, whereby, upon operation to the "on position, the switch lock is first released, and after the enclosure is locked closed the switch is operated tothe on position. I

A further object of this invention an improved enclosed electric safety switch, in which upon movement from on" position to open position, operation of the switch to off position occurs before the position is reached where the enclosure may be unlocked.

The operation of disconnect switches used in enclosedcombination starters for industrial motor control, require features that are of vital importance for safe operation. It is important that the enclosure be locked closed in the oiP' position. Upon opening" of the enclosure it is desirable that movement of the switch operating lever from the exterior of the enclosure release the cover locking means without operation of the disconnect switch to the "on position. This permits the enclosure to be opened for purposes of inspection and test with the disconnect switch in the ofi position.

In the off" position, with the enclosure open, it is desirable that the disconnect switch be locked in the ofi" position. For purposes of test and inspection, it is advantageous to be able, when the enclosure is opened, to operate the switch to the "on position. This is attained in the safety switch herein described by means of a switch lock that can be released by an electrician to permit operation to the on position.

It is also desirable that the disconnect switch be arranged so that it is returned to the locked ofl" position before closing of the enclosure.

With the enclosure closed, operation of the switch operating lever'frpm the exterior of the enclosure should first lock the enclosure and is to secure then operate the disconnect switch to the on position.

The desired features of operation are obtained in the safety switch herein described and shown in detail in the drawings accompanying this specification.

Figure 1 is a front view of a combination starter showing by means of partial cut-out sections, the safety switch operating means, the disconnect switch, and the electromagnetic starter contained within the enclosure.

Figure 2 is a partially sectioned view taken along the lines 2-2 shown in Figure 1.

Figure 3 is a partially sectioned view taken along the lines 33 in Figure 1.

Figure 4A is a section of the disconnect switch operating mechanism and switch operating lever taken along the lines lA-lA in Figure 1, with the disconnect switch in the ofi" position and the switch lock released.

Figure 4B is a section of the disconnect switch operating mechanism and switch operating lever taken along the lines 4A--4A in Figure 1, with the disconnect switch in the on position and the enclosure locked closed.

The combination starter shown in Figure 1 comprises an enclosure l, a disconnect switch l4 and electromagnetic switch l5 mounted within enclosure I, and an operating handle 6 mounted on the front of enclosure l operable to actuate the disconnect switch 14 and to lock or unlock the enclosure I. Disconnect switch is electrically connected to electromagnetic switch 15 by means of connectors 50. Combination starters of this type include a wide variety of combinations including fuse blocks, manual starting switches, and automatic starting switches. The preferred form herein described shows the disconnect switch in combination with an electromagnetic starter.

The enclosure I includes a box 3 having a back or bottom 4 and a hinged cover 2. A mounting plate 5 is attached to the bottom of the box. The mounting plate 5 is used to support disconnect switch l4 and electromagnetic switch Ii. Switch operating handle 6 is mounted on'the front face of the cover 2 and has attached to it on the inside wall of cover 2, a lever I having a projecting extension 8 that engages the switch operating lever 24. The operating handle 6 has on the front face of the cover, a locking device a operable to engage recess l0 in cover 2 to lock lever 6 in the off position. The locking position of locking means 9 is shown in broken lines on Figure 2 and is maintained by one, two orthree padlocks, not

shown, inserted in the openings 5| of locking means 9. On the inside wall of cover 2, there is mounted a formed piece ll including stops i2 and a cover lock i3. The formed piece II is shown best in Figures 2 and 3.

The disconnect switch l4 includes two mounting brackets i6 and I1 to which is attached an insulating block l8 mounting three pair of statlonary switch contacts 52. The bracket ll supports an over-center switch operating mechanism 49. Brackets l6 and I1 jointly support'the U- lever 29 at bearings 2| and 22. Lever is coupled to cross bar i9 by pins 23. Lever 20. actuates cross bar l9 and three pair of bridging contacts 53 operable to engage contacts 52. The U-lever 29 is operated by the over-center switch mechanism 49. Over-center switch operating mechanism 49 includes switch operating lever 24 pivotally mounted on hearing 22. Lever 24 includes bracket 23, an opening 28, a cover locking pin 29, stop pin 34, and a recess 39 for the extension 8 of operating handle lever I. Recess includes an opening 3|, cam surface 33, under cut portion 32 and cam surface 54.

The U-lever 20 includes a bracket 21 that projects through the opening 28 in lever 24. Spaced between bracket 21 and bracket 25 is a compression spring 29. The main bearing 22 jointly supports U-lever 23 and switch operating lever 24. Brackets 23 and 21 are so located with reference to main bearing 22 that upon operating of lever 24, U-lever 29 and cross bar l9 are operated by snap action from "01! to on positions.

A releasable lock 43 is pivotally mounted on the lever 24 to lock the switch mechanism in the 06" position. The releasable lock 43 includes a lever 44, a pivot 45 and a spring 46. Lever 44 has a hooked portion 41 positioned to engage the U- lever 23 when the switch is in the 011" position to lock-the entire switch mechanism preventing movement to "on" position unless the lock is released. The lock is biased to the lockin position by spring 48. Lever 44 has a cam surface 43 normally extending over a portion of the opening 3| of lever 24 where it can be engaged by lever extension 3 to release the lock 43 prior to operation of the over-center switch operating mechanism 49. when the enclosure I is open, the lock 43 can be released manually to permit operation of the switch for purposes of test and inspection.

A kick-off lever 35 is pivotally mounted on bracket I'I. The lever 35 includes'a cam surface 39, stop 49, a stop 33 projecting through recess 31 in bracket l1, and a cam surface 42. In operating lever 24 to actuate the switch from "on to 012" position, pin 34 engages cam surface 39 moving kick-off lever 33 so that cam surface 42' n ages the cam surface 4| on lever 29 positively moving the contacts to open position in the event that the contacts are welded closed. This operation occurs simultaneously with the actuation of the snap action mechanism. In the normal operation to the 08" position the opening occurs entirely by the over-center mechanism. It is only in the event that the contacts are welded that the kick-on mechanism is effective to positively disengage the contacts.

In the "oi!" position of the operating handle 0, cover 2 is held closed by lever extension 9 engaging the under-cut portion 32 of lever 24. This position is maintained by locking the handle 8 to Prevent movement thereof as described above.

The cover 2 of enclosure l is opened by moving operating lever to a position where the lever extension I is opposite the opening 3| of lever 24.

In this position the lever extension 3 does not engage the under-cut portion 32 of lever 24 and the cover 2 is free to be opened. This disconnect switch i4 remains locked in the off position when the cover is opened.

When the enclosur is opened, all parts of the combination starter are disconnected from the line except the line connections to disconnect switch I4. If for purposes of test and inspection an electrician or other qualified person desires to operate the starter, operation to the on position can be made with" the enclosure open by first releasing the locking lever 43 and pushing lever 24 to the on" position. This operation is not obvious to the ordinary workmen and can only be performed by reaching the switch operatin mechanism. An electrician having knowledge of the proper operation of the switch can safely operate the switch to on position by exercising reasonable care.

Operation to the on position with the enclosure closed is shown in Figures 4A and 4B. The operating handle 6 is operated to the right and lever extension 8 engages cam surface 49 of releasable lock 43, moving the releasable lock 43 to the unlocked position shown in Figure 4A. Further movement of the lever extension 9 moves lever 24 to an intermediate position where pin 29 engages cover lock i3 preventing opening of the enclosure. After reaching the cover locking position, further movement of lever extension 8 then completes the operation to on position as shown in Figure 43.

Operation from "on position to "oiIf position with the enclosure "closed follows in general a reversal of the operations to "on position. Lever extension 8 engages lever 24 at cam surface 54 to move the switch to "off position with the cover "closed as shown in Figure 2.

The cover locking position shown in Figure 2 is established at the beginning of th operation to the 011" position so that the cover is locked at all times during movement to "of!" position. Upon completion of the operation to f p tion the releasable lock 43 resets to maintain the locked position when the cover is opened.

I claim as my invention:

1. In a manually operable safety switch comprising a switch mounted within an enclosure having a removable cover, switch operating mechanism within said enclosure operable to actuate said switch to "on" or "oil" positions, a second switch operating mechanism mounted on said cover and operable from the exterior of the enclosure and arranged to be in engagement to actuate said first switch operating mechanism when the enclosure is closed and a releasable switch locking means to lock said switch in the "01! position and operable by said second switch operating mechanism to its unlocked position when the said two switch operating mechanisms are in their engaged position.

2. In a manually operable safety switch comprising a switch mounted with an enclosure having a removable cover, switch operating mechanism within said enclosure operable to actuate said switch to "on" or 011" positions, a second switch operating mechanism mounted on said cover and operable from the exterior of the enclosure and arranged to be in engagement to actuate said first switch operating mechanism when the enclosure is closed and a releasable switch locking means carried by said first switch operating mechanism to lock said switch in the "oil!" position and operable by said second switch ing means, an operating handle mounted on said cover and operable from'the exterior of the enclosure to engage said switch operating lever to operate said switch to on or "of!" positions, and cover locking means on said cover; said operating handle in the o position engaging said first cover locking means to lock said cover closed; said second cover locking means engaging the locking means on said cover to lock said cover closed upon operation of said switch by said operating handle to the "on position; and

A said operating handle having a position within the range of said off" position where the handle can be disengaged from the first cover locking means to allow the cover to open.

4. An enclosed manually operable safety switch comprising an enclosure, a removable cover for said enclosure, a switch located within the enclosure, an operating handle mounted on said cover and operable from the exterior of the enclosure to operate said switch to on or "ofl positions, locking means for said cover when said switch is in ofP' position operable by said operating handle, and a second locking means for said cover when said switch is in "on position operable by said operating handle; operation of said safety switch by said operating handle to the oil position locking said cover by said first cover locking means; operation of said safety switch by said operating handle to the "on position locking said cover closed by said second locking means; and said operating handle having a position within the range of said oif position where both locking means are ineffective,

permitting opening of the enclosure when the switch is in its "off position.

5. An enclosed manually operable safety switch comprising an enclosure, a removable cover for said enclosure, a switch located within the en-' for said cover when said switch is in "on posi-' tion operable by said operating handle; opera-, tion of said safety switch bysaid operating handle from "on" to "o positions rendering said first cover locking means effective before release of said second cover locking means and before movement of said switch from "on to oil' positions; operation of said safety switch by said operating handle from oil to o position rendering said second cover locking means effective before movement of said switch from "ofi to "on position; and said operating handle having a po tion within the range of ,saidfofl" position where both locking means are' inefiective, permitting opening of the enclosure when the switch is in its "oif position.

6. An enclosed manually operable safety switch comprising an enclosure, a removable cover for said enclosure, a switch located within said enclosure, a switch operating mechanism located within said enclosure, an operating handle mounted on said cover actuating a lever on the interior of said enclosure which lever cooperates with said switch operating mechanism, when said cover is closed, to operate said switch to on or off positions, a cover locking member on the interior wall of said cover, a second cover locking member on said switch operating mechanism, and a third cover locking member on said switch operating mechanismf operation of said safety switch by said operating handle to the off"' position locking said cover closed by engagement of said lever with said second cover locking member; operation of said safety switch by said operating handle to the on" position locking said cover closed by engagement of said third cover locking member with said cover locking member on said cover; and said operating handle having a position within the range of said off position where said lever can be disengaged from the second cover locking member to allow the cover to open.

'7. An enclosed manually operable safety switch comprising an enclosure, a removable cover for said enclosure, a switch located within said enclosure, a member inside said cover to operate said switch and an operating handle mounted on said cover and operablefrom the exterior of said enclosure and having a part extending through an opening in said cover and arranged to engage said member and to operate said switch to on" or on? positions; operation of said safety switchby said operating handle to a first position actuating said switch to off position I cover locks are ineffective permitting opening of said enclosure when said switch is in its off position.

8. An enclosed manually operable safety switch comprising an enclosure, a removable cover for said enclosure, a switch located within said enclosure, a cover lock for said enclosure when said switch is in off position, a second cover lock for said enclosure when said switch is in "on position, a releasable switch lock associated with said switch and within said enclosure, and a common operating means comprising an operating handle mounted on the exterior of said cover and a lever on the interior wall of said cover cooperating with said switch, cover locks and switch lock when the cover is closed to actuate said switch to "of!" position and lock said closure, a switch operating mechanism located within said enclosure, an operating handle mounted on said cover actuating a lever on the interior wall of said cover which lever cooperates with said switch operating mechanism, when said cover is closed, to operate said switch to on or "of!" positions, a cover locking member on the interior wall of said cover, a second cover locking member on said switch operating mechanism, and a releasable switch locking means associated with said switch operating mechanism, said operating handle in the oi! position positioning said lever in cover locking engagement with said second cover locking member; and said operating handle upon movement toward the n" position disengaging said lever from said St. and cover locking member and releas. 1 said switch locking means to permit eration of said switch to "on" position.

10. An enclosed manually operable safety switch comprising an enclosure, a removable cover for said enclosure, a switch located within said enclosure, a switch operating mechanism located within said enclosure, an operating handle mounted on said cover actuating a lever on the interior wall of said cover which lever cooperates with said switch operating mechanism, when said cover is closed, to operate said switch to on" or "oil" positions, a cover locking member on the interior wall of said cover, a second cover locking member on said switch operating mechanism, a third cover locking member on said switch operating mechanism, and a releasable switch locking means associated with said switch v operating mechanism; said operating handle in the "oi!" position positioning said lever in cover locking-engagement with said second cover looking member; said operating handle upon movement toward the on" position disengaging said lever from said second cover locking member and releasing said switch locking means to permit operation of said switch to on'fposition; and

said operating handle in the "on position positioning said third cover locking member in cover locking engagement with the cover locking member on the interior wall of said cover.

11. An enclosed manually operable safety switch comprising an enclosure, a removable cover for said enclosure, 9. switch located within operating mechanism, a third cover locking member on said switch operating mechanism, and a releasable switch locking means associated with said switch operating mechanism, said operating handle in the "01! position positioning said lever in cover locking engagement with said second cover locking member; said operating handle upon movement toward the on position disengaging said lever from said second cover lockin member and releasing said switch locking means to permit operation oi! said switch to "on" position; said operating handle in the "on" position positioning said third cover locking member in cover locking engagement with the cover locking member on the interior wall or said cover; and upon movement by said operating handle from "oil" to "on position said third cover locking member moving into cover locking engagement with said cover locking member on the interior wall of said cover before actuation of said switch to the on position.

J. QUAST. 

